A Native American overlooking the newly completed railroad in 1868

In the United States, Native Americans are considered to be people whose
pre-Columbian ancestors were indigenous to the lands within the nation’s modern boundaries.

These peoples were composed of numerous distinct tribes, bands, and ethnic groups, and many of these groups survive intact today as sovereign nations.

The terms Native Americans use to refer to themselves vary regionally and generationally, with many older Native Americans self-identifying as “Indians” or “American Indians”, while younger Native Americans often identify as “Indigenous” or “Aboriginal.” Which terms should be used to refer to Native Americans has at times been controversial. The term “Native American” has been adopted by major newspapers and some academic groups, but has not traditionally included Native Hawaiians or certain Alaskan Natives, such asAleut, Yup’ik, or Inuit peoples. Indigenous American peoples from Canada are known as First Nations.

Since the end of the 15th century, the migration of Europeans to the Americas has led to centuries of exchange and adjustment between Old and New World societies. Most Native American groups had historically lived as hunter-gatherer societies and preserved their histories by oral traditions and artwork, which has resulted in the first written sources on the conflict being authored by Europeans.

At the time of first contact, the indigenous cultures were quite different from those of the proto-industrial and mostly Christianimmigrants. Some of the Northeastern and Southwestern cultures in particular were matrilineal and operated on a more collective basis than the Europeans were familiar with. The majority of Indigenous American tribes maintained their hunting grounds and agricultural lands for use of the entire tribe. Europeans at that time had patriarchal cultures and had developed concepts of individual property rightswith respect to land that were extremely different. The differences in cultures between the established Native Americans and immigrant Europeans, as well as shifting alliances among different nations in times of war, caused extensive political tension, ethnic violence, and social disruption. Even before the European settlement of what is now the United States, Native Americans suffered high fatalities fromcontact with European diseases spread throughout the Americas by the Spanish to which they had yet not acquired immunity. Smallpox epidemics are thought to have caused the greatest loss of life for indigenous populations, although estimates of the pre-Columbian population of what today constitutes the U.S. vary significantly, from one million to eighteen million.

After the thirteen colonies revolted against Great Britain and established the United States of America, President George Washingtonand Henry Knox conceived of the idea of “civilizing” Native Americans in preparation for assimilation as U.S. citizens.
Assimilation (whether voluntary, as with the Choctaw, or forced) became a consistent policy through American administrations. During the 19th century, the ideology of manifest destiny became integral to the American nationalist movement. Expansion of European-American populations to the west after the American Revolution resulted in increasing pressure on Native American lands, warfare between the groups, and rising tensions. In 1830, the U.S. Congress passed the Indian Removal Act, authorizing the government to relocate Native Americans from their homelands within established states to lands west of the Mississippi River, accommodating European-American expansion. This resulted in the ethnic cleansing of many tribes, with the brutal, forced marches coming to be known as The Trail of Tears.